Just got myself a co2 tank designed to fill small paintball tanks.
I plan to use this mostly for combat robotics and possibly for a MIG set up when I get MIG.
I do have SCUBA experience, an air compressor and a TIG set up. But co2 seems to be a bit of a different horse as it is stored in liquid form.
Looking for information sources on handling this safely. Favorite books, web sites, free advice...
Tanks :-) for any help.
DOC
SCUBA tanks are a lot higher pressure than CO2. The only real issue with CO2 is the potential for frostbite if you manage to release it in liquid form on yourself. Just download the MSDS from the Airgas site.
Not quite the only issue. Even a CO2 tank in a fire is a bomb, even it if puts the fire out when it blows. And if you happen to have confined spaces, particularly a cellar or similar, there is a real asphyxiation risk from a leak. Fire fighters using CO2 know that if they get a taste in the mouth like a fizzy drink then it is time to get out.
Did you get one for paintball filling or for welding? the paintball unit has a tube inside the tank so liquid comes out when its upright, can't be used to weld. A weld tank has to be upside down to dispense liquid.
a small tube and valve kit is sold to hook the paintball tank up to the big tank. Comes with directions. basically you vent a little gas out of the paintball can and the pressure difference forces liquid across. Biggest issue with filling is freezing a line up - go slow.
DON'T OVERFILL. You need 20% headspace. Use a scale. "The kid" filled paintball tanks for all his friends when he was home. He overfilled one and, not knowing of a problem, put it in the car and started driving. It popped the relief valve with a bang while they were driving. They almost had an accident trying to jump out of the car cause they thought a bomb had went off.
Karl
I don't think so - they have pressure relief valves. Plugs, actually, IIRC.
I don't think so - breathing just a little would be so distressing that you'd immediately get-the-hell-out. It's the rise in CO2 concentration in our lungs that makes it so hard to hold your breath for very long. There's still plenty of oxygen in your lungs but the rising CO2 says: BREATH! BREATH!! You start experiencing that in your cellar and you'll be out of there long before asphyxiation is a risk.
Bob
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I recall the air tanks were around 3000 PSI and gather that co2 is somewhere around the 600 mark.
And I gather that the co2 stays at a constant pressure as long as there is liquid in the tank. That sound right?
And paintball tanks are loaded by weight, not pressure. So there's no point in putting a gage on a tank?
DOC
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I don't plan to do any paintball. It's more for combat robotics. But I would assume that. from a procedure point of view, this would be like paintball.
The tank I have is for paintball and has a siphon.
the paintball unit has
Does securing the tank upside down make any sense?
I've got a small tube like that. Made by Pure Energy. Didn't get any instructions. But it wasn't too hard to figure out.
I was able to use it to "fill" a 9 oz tank but don't have a scale to check the wieght.
When you say don't overfill I assume you mean that there shouldn't be too much liquid in a tank?
Thanks, DOC
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Our SCBA tanks are pressurized up to 2215PSI. I have no idea where that number comes from. There are also 6000PSI tanks I seem to recall but...in a fire, one 2215PSI tank is all I can go through without being tired, not sure how much longer the 6000PSI would last but, longer than me.
Probably not. Propane tanks are similar, pressure is nearly irrelevant, level of liquid is the key. If, as you say, CO2 is in a liquid form in the tank.
Aluminum SCUBA tanks are usually 3,000PSI, some are 3,300PSI. Steel SCUBA tanks are usually 2215PSI, though there are some HP versions. I've seen composite SCUBA tanks that run at 4,500PSI and that is also a common pressure for fire fighting SCBA tanks.
The 2215PSI SCBA tanks are typically older ones from what I've seen and seen to be going away. I've not seen any portable SCUBA or SCBA tanks running at 6,000PSI, but cascade tank banks often operate that high so that they can fully fill the 3,000PSI tanks for a sizable draw down before the compressor needs to operate again.
Pete C.
A decent digital food or postal scale would be a good investment.
The bulk tank itself should require no more care than your other high pressure bottles.
I understand that care is required in filling the small paintball tanks to insure there's always an adequate gas headspace above the liquid. If not, heat can cause the liquid to expand and explode the tank.
You don't need to, you got the one for filling tanks. But you can't weld with this tank.
Correct. If you put too much in you're going to pop something when everything warms back up from the filling process. Buy a scale, eBay is your friend here.
Karl
Weigh the tank on an accurate scale while it is empty. Add the rated capacity to that weight and that will be the maximum that the tank should ever weigh after a fill.
If you find you have overfilled, no biggie, (other than it being a waste) just bleed off some CO2 untill you are at the weight desired.
If you do not bleed a bit of CO2 off the tank (recieving) prior to filling, or you do not place the tank into a freezer or on ice, it "usually" (!!!) will not take a full charge, as the difference in pressure is not great enough to flow enough liquid to get a rated fill. Usually!
Most often, to get a full load on a paintball cylinder, you must either be doing several at a time (which will load the siphon tube with liquid) or you must give the tank a squirt, bleed it off (which chills the tank) then fill it.
A digital scale that you can zero easilly will allow you to weigh the fill, by zeroing with the empty cylinder on the scale, then weighing the filled one, to see how much you got.
For personal use, I do not worry about getting right to the rated cap. If I am paying by the rated cap. of the tank for a fill, I want to get all the ounces I pay for.
FWIW, a pressure gauge is only really useful as an indicator that you no longer have liquid CO2 in your tank and are running on gas pressure only.
Somewhere out there on the web is a US Navy chart that shows the pressure-temperature relationship on a CO2 cylinder, including the curves for overfills. Normal pressure is pretty steady at around 800 psi (varies with temperature) but an overfill along with some heat can drive the pressure WAY up WAY fast!
Overall I'd rate the risk of having a CO2 tank around as less than the risks posed by the propane tank on the BBQ.
Cheers Trevor Jones
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